Information display apparatus

ABSTRACT

An information display apparatus capable of reducing the viewpoint movement of a driver and achieving safer driving in consideration of the relationship between the traveling speed and the stopping distance of a vehicle is provided. The information display apparatus is configured to display image information in a transportation and comprises a HUD apparatus disposed between a windshield of the transportation and an instrument panel of the transportation. The HUD apparatus detects a viewpoint position of a driver; and displays a virtual image of the image information in front of the transportation by reflecting light emitted from the HUD apparatus to display the image information by the windshield. The HUD apparatus is configured to set a display position of the virtual image in accordance with movement of the viewpoint position of the driver who is driving the transportation.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.17/841,676, filed Jun. 16, 2022, which is a continuation of U.S.application Ser. No. 16/982,593, filed Sep. 21, 2020 (now U.S. Pat. No.11,398,208), which is based on PCT filing PCT/JP2019/005748, filed Feb.18, 2019, which claims priority to JP 2018-054592, filed Mar. 22, 2018,the entire contents of each are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an information display apparatusconfigured to project an image on a windshield of a so-calledtransportation that moves to carry people such as automobile, train,aircraft, or the like.

BACKGROUND ART

A so-called head-up-display (HUD) apparatus configured to project imagelight onto a windshield of a vehicle to form a virtual image, therebydisplaying traffic information such as route information and trafficcongestion information and vehicle information such as remaining fuelamount and cooling water temperature has already been known from, forexample, Patent Document 1 below, and downsizing for disposing a mainbody of the HUD apparatus between the steering wheel and the windshieldin front of the driver's seat is desired.

In this type of information display apparatus, for the purpose of makingit easier for the driver to recognize the information, it is required toform the virtual image at a plurality of positions in accordance withthe visual recognition position of the driver, in other words, to adjustthe distance at which the virtual image is formed to the visualrecognition position of the driver. Thus, as disclosed in, for example,Patent Document 2 below, there is an information display apparatus inwhich an image is formed at each of a distant position (long distance)and a close position (short distance) from a driver.

RELATED ART DOCUMENTS Patent Documents

Patent Document 1: Japanese Patent Application Laid-open Publication No.2009-229552

Patent Document 2: Japanese Patent Application Laid-open Publication No.2015-034919

SUMMARY OF THE INVENTION Problems to Be Solved By the Invention

In the above-mentioned conventional HUD apparatus, various types ofinformation are provided to the driver by projecting image light ontothe windshield of a vehicle to form a virtual image, but the provisionof the information in consideration of larger screen usingnext-generation technologies such as the big data (high precision 3D mapinformation) and the AI information (predicted hazard information, etc.)has not been sufficiently taken into account. Therefore, as will bedescribed in detail later, there is still room for improvement from theperspective of improving the safety by reducing the viewpoint movementof the driver, and the structure of the HUD apparatus (in particular,the increase in the set volume of the HUD) for making it possible to setthe virtual image display position to the optimum position has also notbeen sufficiently taken into account.

Therefore, an object of the present invention is to provide aninformation display apparatus capable of displaying information in sucha way that the viewpoint movement of the viewer is made smoother inconsideration of the viewpoint movement of the driver and therelationship between the traveling speed and the stopping distance ofthe vehicle.

Means for Solving the Problems

The present invention has been made in light of the above-mentionedbackground technology and the problem thereof, and an example thereof isan information display apparatus configured to display image informationin a transportation. The information display apparatus comprises a HUDapparatus disposed between a windshield of the transportation and aninstrument panel of the transportation, wherein the HUD apparatusincludes: driver's viewpoint position detecting means configured todetect a viewpoint position of a driver; and a virtual image opticalsystem configured to display a virtual image of the image information infront of the transportation by reflecting light emitted from the HUDapparatus to display the image information by the windshield, and theHUD apparatus is configured to set a display position of the virtualimage in accordance with movement of the viewpoint position of thedriver who is driving the transportation, detected by the driver'sviewpoint position detecting means.

Effects of the Invention

According to the present invention described above, by the informationdisplay using a virtual image in accordance with the movement ofviewpoint position of a driver who is driving a transportation andfurther by the information display in consideration of the relationshipbetween the traveling speed and the stopping distance of a vehicle, theviewpoint movement of the driver is reduced and the safer driving isachieved. In particular, by applying to so-called alert display(information) or the like, which is the information for giving a warningof the presence of a pedestrian in front of the vehicle and a precedingvehicle, it is possible to perform the display to a dangerous objectfarther than the stopping distance of the own vehicle.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 is a diagram showing an upper surface and a windshield of anautomobile in which an information display apparatus according to anembodiment of the present invention is mounted;

FIG. 2 is a schematic diagram of a windshield viewed from a driver'sseat of the automobile in which the information display apparatusaccording to the present invention is mounted and a diagram showing anenlarged image display region (area) of the HUD;

FIG. 3 is an explanatory diagram of setting conditions of a viewpoint(EYE Point);

FIG. 4 is a diagram showing an example of the relationship between thetraveling speed and the stopping distance of a vehicle;

FIG. 5 is a block diagram and a schematic configuration diagram showinga peripheral equipment configuration of a HUD apparatus 1 according toan embodiment of the present invention;

FIG. 6 is a diagram showing a display position (range) of a virtualimage in a HUD image display region while using an alert display for apedestrian as an example;

FIG. 7 is a diagram showing a display position (range) of a virtualimage in a HUD image display region while using an alert display for apreceding vehicle as an example;

FIG. 8 is a diagram showing an example of a traveling speed of a vehicleand a range of viewpoint movement;

FIG. 9 is a diagram showing an example of a traveling speed of a vehicleand a range of viewpoint movement;

FIG. 10 is an explanatory diagram of a relationship between the volumeof information display apparatus and the enlarged image display region(area) of the HUD;

FIG. 11 is a diagram showing an example of a configuration and anarrangement (layout) of a HUD apparatus which is an information displayapparatus suitable for downsizing; and

FIG. 12 is a diagram showing an example of a configuration and anarrangement (layout) of a HUD apparatus which is an information displayapparatus suitable for downsizing.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, an embodiment of the present invention and various exampleswill be described with reference to drawings and the like. Note that thefollowing descriptions show specific examples of the contents of theembodiment, the present invention is not limited to these descriptions,and various changes and modifications can be made by a person havingordinary skill in the art within the scope of the technical ideadisclosed in this specification. In addition, in all the drawings fordescribing the present invention, components having the same functionare denoted by the same reference characters, and repetitive descriptionthereof will be omitted in some cases. Prior to the description of theembodiment of the present invention, the display position of the virtualimage, which is a feature of the present invention, will be describedbelow.

FIG. 1(a) is a top view of an automobile in which the informationdisplay apparatus according to the present invention is mounted, and awindshield as a projection-receiving member 6 exists in a front part ofthe driver's seat of a vehicle body 101. Note that the inclination angleof the windshield with respect to the vehicle body differs depending onthe type of vehicle. Furthermore, the inventors also investigated theradius of curvature of the windshield in order to realize the optimalvirtual image optical system. As a result, as shown in FIG. 1(b), thewindshield had a radius of curvature Rh in the horizontal directionparallel to the contact plane of the automobile and a radius ofcurvature Rv in the vertical direction orthogonal to the horizontalaxis, which are different from each other, and Rh and Rv generally hadthe following relationship.

Rh>Rv

It was also found that the difference in radius of curvature, that is,the ratio of Rh to Rv was within the range of 1.5 to 2.5 times in manycases.

Next, the inventors also investigated commercial products for theinclination angle of the windshield. As a result, although it varieddepending on the vehicle body type, it was 20 to 30 degrees for thelight automobile and one-box type, 30 to 40 degrees for the sedan type,and 40 degrees or more for the sports-car type.

FIG. 2(a) is a schematic diagram of the windshield 6 viewed from adriver's seat of the automobile in which the information displayapparatus according to the present invention is mounted, and an enlargedimage display region (area) of the HUD is provided near the center ofthe windshield 6 in front of a steering wheel 43 as shown in FIG. 2(a).FIG. 2 (b) shows the details of the image display region (area) of theHUD, and as shown by the arrows in the drawing, the display region movesup and down in accordance with the change in the depression angle, andits width is varied in accordance with the change in the viewing angle(horizontal). Specifically, as an example, the depression angle is setto 3.0° when driving in the city area at 30 to 60 km/h (city area mode),and it is switched (reduced) to 1.9° when driving at a high speed of 60to 100 km/h (high speed mode). Further, the viewing angle (horizontal)is 10° in the city area mode and is narrowed to 9° in the high speedmode. Note that the viewing angle (vertical) is constant at, forexample, 2.2°. In the image display region (area) of the HUD above, aswill be described later, the upper end thereof is 100 m in front of thevehicle and the lower end thereof is 25 m in the high speed mode(depression angle=1.9°). In the city area mode (depression angle=3.0°),the upper end thereof is 25 m in front of the vehicle and the lower endthereof is 19 m. Note that the switching between the city area mode andthe high speed mode could be made based on the information from thenavigation system described below.

FIG. 3 is an explanatory diagram of setting conditions of a viewpoint(EYE Point). This EYE Point is set based on an R Point which is the axisof rotation between the thigh and the trunk of the human body (model)and an H Point defined when the human body (model) is seated in thestate where the seat is located at the backmost position, the seatheight is at the bottom, and the seat angle is at 25 deg (degrees), andthe depression angle is determined by the angle of the center line tothe HUD display from this EYE Point.

Further, a reference character 60 in FIG. 2 denotes a camera including,for example, an infrared camera attached to a part of the steeringwheel, and it constitutes means for detecting the driver's viewpointhere. Note that the viewpoint monitoring camera which is the driver'sviewpoint detecting means, does not necessarily have to be attached to apart of the steering wheel as described above, and may be attached to,for example, a part of a dashboard or a part of a windshield as long asit can detect the viewpoint of the driver.

<Relationship Between Traveling Speed and Stopping Distance of Vehicle>

Normally, the distance required before a traveling vehicle stops(stopping distance) changes in proportion to the traveling speed of thevehicle as shown in FIG. 4 . Namely, a vehicle running at a speed of 30km/h needs a stopping distance of 14 m which is a total of the freerunning distance and the braking distance, the stopping distance of 52 mis required at a speed of 70 km/h, and the stopping distance of as muchas 93 m is required at a speed of 100 km/h.

On the other hand, the HUD apparatus which is an information displayapparatus provides various types of information to the driver byprojecting image light onto the windshield of an automobile to form avirtual image, but the virtual image is generally displayed at thepreset position in front of the vehicle in most cases. However, when theabove-mentioned relationship between the traveling speed and thestopping distance of the vehicle is taken into account, it has beenfound that the so-called alert display (information) or the like whichis information for giving a warning of the presence of a pedestrian infront of the vehicle and a preceding vehicle makes it possible to reducethe viewpoint movement of the driver and achieve the safer driving bydisplaying the alert to a dangerous object farther than the stoppingdistance of the vehicle.

Namely, the present invention provides a HUD apparatus capable ofachieving the safer driving in consideration of the relationship betweenthe traveling speed and the stopping distance of the vehicle describedabove, and further provides a HUD apparatus capable of solving theproblem that occurs when the display position of the virtual image(distance in front of the vehicle) is made variable, that is, theincrease in the apparatus volume due to the size increase of the opticalsystem including the concave mirror used in the above-mentionedconventional technology.

<Information Display Apparatus>

FIG. 5 is a block diagram and a schematic configuration diagram showinga peripheral equipment configuration of the HUD apparatus 1 according toan embodiment of the present invention, and a HUD apparatus configuredto project an image on a windshield of an automobile will beparticularly described as an example here.

The HUD apparatus 1 is configured to display various types ofinformation reflected by the projection-receiving member 6 (windshieldin this embodiment) as virtual image VI (Virtual Image) in order to formvirtual images V1 to V3 at a plurality of positions in front of the ownvehicle in the driver's line of sight 8. Note that any member can beapplied as the projection-receiving member 6 as long as the informationcan be projected on the member, and it may be a combiner other than thewindshield mentioned above. Namely, in the HUD apparatus 1 according tothis embodiment, a virtual image is formed at each of a plurality ofpositions in front of the own vehicle in the driver's line of sight 8 soas to make the driver visually recognize the image, and examples of theinformation displayed as the virtual image include an alert display(information) that gives a warning of the presence of a pedestrian infront of the vehicle and a preceding vehicle, vehicle information, andforeground information captured by a camera (not shown) such as amonitoring camera or an around viewer.

In addition, the HUD apparatus 1 includes an image projection device 11configured to project image light for displaying information, anintermediate image forming unit 4 configured to form an image of thelight from the image projection device 11, an optical component 5configured to converge or diverge the image information (image light)that has been formed in the intermediate image forming unit 4, and acontrol device 30 configured to control the image projection device 11mentioned above. Note that the above-mentioned optical component 5 is avirtual image optical system described below, and includes a concavemirror to reflect light. Further, the light reflected by the opticalcomponent 5 is reflected by the projection-receiving member 6 and isdirected to the driver's line of sight 8 (Eye Box: described in detaillater) .

The intermediate image forming unit (or intermediate image display unit)4 mentioned above has a function of forming an image of the light fromthe image projection device 11, and is configured of, for example, amicrolens array in which microlenses are two-dimensionally arranged. Inthis embodiment, an optical element 21 and an optical element 22 arearranged between the intermediate image forming unit 4 and the opticalcomponent 5 composed of the concave reflecting mirror constituting aneyepiece optical system. The first purpose of arranging the opticalelement 21 and the optical element 22 is to set the virtual imageforming positions at a plurality of positions (three positions in FIG. 5) in front of the own vehicle. Further, the second purpose thereof is toperform the aberration correction at the position where the image lightfrom the intermediate image forming unit 4 is separated between theintermediate image forming unit 4 and the optical component 5constituting the eyepiece optical system. With the aberration correctionby these optical elements, even if virtual images are formed atdifferent positions, a plurality of virtual images can be displayed atdifferent magnifications by using the same virtual image optical system.

More specifically, the optical element 21 corrects the aberration of thelight flux that forms the virtual image V1 located at the closestposition, and at the same time, the optical element 22 corrects theaberration of the virtual image V2 located at an intermediate position.Further, since the aberration of the virtual image V3 formed at thefarthest position is optimally designed in the original virtual imageoptical system, no optical element is provided here. However, it goeswithout saying that even if an optical element optimally designed forimproving the aberration correction capability is provided, it does notdepart from the technical idea or the scope of the present invention.Here, as an example, the virtual image V1 is displayed at a distance of14 m or more in front of the vehicle, the virtual image V2 is displayedat a distance of 52 m or more, and the virtual image V3 is displayed ata distance of 93 m or more.

In addition, for convenience of description, the example in which thepositions to generate the virtual images are divided into the distantvirtual image V3, the intermediate virtual image V2, and the closevirtual image V1 and the optical elements 21 and 22 are individuallyprovided has been described in this embodiment, but the presentinvention is not limited to this. For example, in order to continuouslychange the display position of the virtual image from a distant positionto a close position, the position where the virtual image is generatedis changed by changing the spatial optical distance, more specifically,changing the thickness of the optical element in the direction verticalto the screen, and sufficient aberration correction capability isprovided by designing the lens shapes on both surfaces of the opticalelement to have an eccentric aspherical surface shape or a free-formsurface shape. As a result, it goes without saying that even theconfiguration provided with one optical element does not depart from thetechnical idea or the scope of the present invention.

On the other hand, the control device 30 includes a storage device 31and a microcomputer 32. The storage device 31 is composed of anon-volatile storage device in which stored contents are rewritable. Themicrocomputer 32 is mainly composed of a ROM 34 that stores a processingprogram and data whose stored contents need to be retained even when thepower is turned off, a RAM 33 that temporarily stores the processingprogram and data, and a computer having a CPU 35 that executes variousprocesses in accordance with the processing program stored in the ROM 34and the RAM 33.

Among them, the ROM 34 stores a processing program for the microcomputer32 to execute information display process for controlling the imageprojection device 11 so that various types of information such asvehicle information and foreground information are projected on theprojection-receiving member 6. Then, at least a navigation system 61, adriving support electronic control unit (hereinafter, referred to as“driving support ECU (Electronic Control Unit)) 62, and further, theviewpoint monitoring camera 60 mentioned above are connected to thecontrol device 30 as an acquisition source of the vehicle informationand the foreground information.

The navigation system 61 is a device that guides a route to a setdestination in accordance with the result of matching the currentposition detected by a position detecting device with map data stored ina map data storage unit. The map data includes various types ofinformation such as road speed limits, the number of lanes, andinformation about intersections.

The control device 30 acquires, from the navigation system 61 mentionedabove, information such as the speed limit and the number of lanes ofthe road corresponding to the current position where the own vehicle istraveling and the planned travel route of the own vehicle set in thenavigation system 61 as the foreground information (that is, informationdisplayed in front of the own vehicle by the virtual image).

The driving support ECU 62 is a control device that realizes drivingsupport control by controlling a drive system and a control system inaccordance with an obstacle detected as a result of the monitoring by asurroundings monitoring device 63, and examples of the driving supportcontrol include well-known technologies such as cruise control, adaptivecruise control, pre-crash safety, and lane keeping assist.

The surroundings monitoring device 63 is a device that monitors thesurroundings of the own vehicle, and examples thereof include a camerathat detects an object existing around the own vehicle based on an imageof the surroundings of the own vehicle and a sensor device that detectsan object existing around the own vehicle based on the result oftransmitting and receiving sensing waves. Note that, in this embodiment,the surroundings monitoring device 63 also distinguishes between day andnight by detecting (sensing) external light with the camera describedabove.

The control device 30 acquires such information from the driving supportECU 62 (for example, the distance to the preceding vehicle, the azimuthof the preceding vehicle, and the position where the obstacle or thesign exists) as the foreground information. Further, an ignition (IG)signal and vehicle state information are input to the control device 30.Among these pieces of information, the vehicle state information isinformation acquired as vehicle information and includes warninginformation indicating that the amount of fuel remaining in the internalcombustion engine or the temperature of cooling water becomes apredetermined abnormal state. In addition, the vehicle state informationalso includes the information about the operation result of thedirection indicator, the traveling speed of the own vehicle, the shiftposition, and others. The control device 30 described above is activatedwhen an ignition signal is input. The above is the description of theentire system of the information display apparatus according to theembodiment of the present invention.

<Optimization of Virtual Image Display Position>

Next, the display position (range) of the virtual image generated by theabove-described information display apparatus in the HUD image displayregion will be described in detail below, while particularly taking thealert display as an example.

In the information display apparatus according to the present invention,as described above, when providing the alert display for a dangerousobject farther than the stopping distance (for example, a pedestrian infront of the vehicle or a preceding vehicle), the display position(range) necessary for the alert display is obtained based on therelationship between the traveling speed and the stopping distance ofthe own vehicle, and the display position is determined including theoptimum viewing angle (FOV). For example, when the traveling speed is 30km/h, the alert display is performed at a distance of 14 m or more toavoid the danger.

FIG. 6 shows a state in which the above-mentioned alert display isperformed for a pedestrian, and as is clear from the drawing, the alertdisplay for a pedestrian is performed near the lower end of the imagedisplay region (area) of the HUD shown in FIG. 2 during the driving inthe city area. According to this, as is apparent from the left part ofthe drawing, the alert display performed near the lower end of the imagedisplay region (area) of the HUD is displayed at a distance of about 19m in front of the vehicle. On the other hand, during the driving at highspeed, as is clear from the left part of the drawing, the alert displayis performed near the upper end. According to this, the alert displayperformed near the upper end of the image display region (area) of theHUD is displayed at a distance of about 100 m in front of the vehicle.

FIG. 7 shows a state in which the above-mentioned alert display isperformed fora preceding vehicle, and as is clear from the drawing, thealert display for a preceding vehicle is performed near the lower end ofthe image display region (area) of the HUD shown in FIG. 2 during thedriving in the city area. According to this, as is apparent from theleft part of the drawing, the alert display performed near the lower endof the image display region (area) of the HUD is displayed at a distanceof about 19 m in front of the vehicle. On the other hand, during thedriving at high speed, as is clear from the left part of the drawing,the alert display is performed near the upper end. According to this,the alert display performed near the upper end of the image displayregion (area) of the HUD is displayed at a distance of about 100 m infront of the vehicle.

Namely, according to the optimization of the virtual image displayposition described above, the alert display (information) which isinformation for giving a warning of the presence of a pedestrian infront of the vehicle and a preceding vehicle can be displayed for adangerous object farther than the stopping distance of the own vehiclewhile taking the relationship between the traveling speed and thestopping distance of the vehicle into account.

<Movement of Driver's Viewpoint>

Furthermore, the inventors investigated how the driver's viewpointmovement changed depending on the vehicle speed. In FIG. 8 , theviewpoint movement in the case of traveling on a general road at anaverage speed of 50 to 60 km/h for 1 to 3 minutes is shown separately inthe horizontal and vertical directions. FIG. 8(a) shows a range of theviewpoint movement when traveling in the daytime, and FIG. 8(b) showsthe driver's viewpoint movement when traveling at night in the samesection where the data shown in FIG. 8(a) is acquired.

When traveling on a general road at an average speed of 50 to 60 km/h inthe daytime, a viewpoint movement width Vd in the vertical direction was15 degrees and the center of the viewpoint movement was a depressionangle of −2 degrees as shown in FIG. 8(a). Also, a viewpoint movementwidth Hd in the horizontal direction was 28 degrees, and the center ofthe viewpoint was shifted to the left by 5 degrees from the centerbecause the vehicle used for the test was right hand drive vehicle andit traveled on the left lane.

When traveling in the same section at an average speed of 50 to 60 km/hin the nighttime, a viewpoint movement width Vn in the verticaldirection was 11 degrees and the center of the viewpoint movement was adepression angle of −5 degrees as shown in FIG. 8(b). Also, a viewpointmovement width Hd in the horizontal direction was 16 degrees, and thecenter of the viewpoint had a smaller viewpoint movement range than thatof daytime and was shifted to the left by 3 degrees from the center.

Next, when traveling on an express way at an average speed of 80 km/hfor 1 to 3 minutes in the daytime, a viewpoint movement width Vd in thevertical direction was 14 degrees and the center of the viewpointmovement was a depression angle of 2 degrees as shown in FIG. 9(a) .Also, a viewpoint movement width Hd in the horizontal direction was 14degrees, and the center of the viewpoint was shifted to the left by 5degrees from the center because the vehicle used for the test was righthand drive vehicle and it traveled on the left lane.

When traveling in the same section at an average speed of 80 km/h in thenighttime, a viewpoint movement width Vn in the vertical direction was10 degrees and the center of the viewpoint movement was a depressionangle of −5 degrees as shown in FIG. 9(b). Also, a viewpoint movementwidth Hd in the horizontal direction was 2 degrees, and the center ofthe viewpoint had a smaller viewpoint movement range than that ofdaytime and was shifted to the left by 3 degrees from the center.

From the above results, it became clear that the range and center of thedriver's viewpoint movement changed depending on the vehicle speed.Then, the present invention has been made in view of such facts, andmore specifically, the display position of the virtual image which isthe image display position of the information display apparatus ischanged in accordance with the driver's viewpoint movement only or incombination with the optimization of the display position of the virtualimage in consideration of the relationship between the traveling speedand the stopping distance of the vehicle. Namely, the display positionof the virtual image is set in accordance with the movement of theviewpoint position detected by the viewpoint monitoring camera 60described above. According to this, the alert display (information)which is the information for giving a warning of the presence of apedestrian in front of the vehicle and a preceding vehicle can bedisplayed in accordance with the driver's viewpoint movement and can bedisplayed for a dangerous object farther than the stopping distance ofthe own vehicle. Furthermore, it is possible to reduce the driver'sviewpoint movement depending on the driving situation, and as a result,it is possible to further reduce the factors to impede the safe driving.

In addition, the driver's viewpoint movement described above exhibitsdifferent tendencies between the case of traveling in the daytime andthe case of traveling in the nighttime. Namely, according to the factthat the driver's viewpoint movement is narrowed during the driving inthe nighttime than that during the driving in the daytime, it isdetermined whether the vehicle is driving in the daytime or in thenighttime (including the driving in tunnel) by detecting the externallight by the camera constituting the surroundings monitoring device 63,and the display position of the virtual image which is the image displayposition of the information display apparatus can be set inconsideration of the result.

<Volume of Information Display Apparatus>

Next, the relationship between the volume of the above-mentionedinformation display apparatus and the enlarged image display region(area) of the HUD shown in FIG. 2 will be described with reference toFIG. 10 . Namely, the volume of the information display apparatusincreases as the viewing angle (horizontal (H), vertical (V)) of theimage display region (area) of the HUD increases. Specifically, in thecase of the viewing angle of [10×7] and the virtual image distance of(20 m), the set volume of the HUD exceeds 18 L due to the size increaseof the optical system including the concave mirror, which poses theproblem that the information display apparatus cannot be accommodated inthe space between the windshield and the steering wheel which is theplace to install the apparatus. Thus, the structure of the informationdisplay apparatus for solving problem of the increase in the apparatusvolume due to the increase in the viewing angle of the image displayregion (area) of the HUD will be described below.

FIG. 11 and FIG. 12 each show a configuration and an arrangement(layout) of the HUD apparatus 1 which is an information displayapparatus suitable for downsizing. In these drawings, mainly in FIG. 12, a concave (free-form surface) mirror 5 a configured to project theimage light to form a virtual image through the windshield 6 (see FIG. 1), a correction lens group 2 for correcting the distortion andaberration caused in the projection, the image display device 11, and abacklight light source 10 using a light emitting diode constituting abacklight as a light source are provided in order from the downstreamside. Note that 7 denotes a housing serving as an exterior case.Further, in order to suppress the P wave component of sunlight thatenters the HUD apparatus 1, as an example thereof, optical means 3 forsuppressing the P wave component is provided between the lens group 2and the image display device 11. Then, an opening through which theimage light is projected toward the windshield of the automobile isformed in the upper surface of the housing 7, and the opening is coveredwith an antiglare plate 41 (glare trap). Further, although not shownhere, a concave mirror driving unit configured of an electric motor orthe like for adjusting the position of the concave mirror 5 a isprovided integrally with the concave mirror 5 a. Then, these componentsare modularized and formed compactly while ensuring a minimum distancebetween the LCD and the concave mirror.

In order to expand the viewing angle in such a configuration andarrangement, for example, the concave mirror 5 a is rotationally driven,and in order to realize the distant virtual image distance, thecollimator optical system 3 is appropriately set, so that desiredcharacteristics can be realized. Alternatively, it is also possible toenlarge the image display region (area) of the HUD by adding a secondinformation display apparatus configured to obtain a real image byscanning the windshield with laser light by using MEMS elements.

Namely, by adopting the HUD apparatus 1 having the above-describedconfiguration and arrangement, the above-mentioned problem of theincrease in the apparatus volume due to the increase in the viewingangle of the image display region (area) of the HUD can be solved, andthe HUD apparatus can be accommodated in the installation place, thatis, the space between the windshield and the steering wheel.

In the foregoing, the information display apparatus according to variousembodiments of the present invention has been described above. However,the present invention is not limited to the above-described embodiments,and includes various modifications. For example, the above embodimentshave described the entire system in detail in order to make the presentinvention easily understood, and the present invention is notnecessarily limited to those having all the described configurations.Also, a part of the configuration of one embodiment may be replaced withthe configuration of another embodiment, and the configuration of oneembodiment may be added to the configuration of another embodiment.Furthermore, another configuration may be added to a part of theconfiguration of each embodiment, and a part of the configuration ofeach embodiment may be eliminated or replaced with anotherconfiguration.

REFERENCE SINGS LIST

1 . . . HUD apparatus, 4 . . . intermediate image forming unit, 5 . . .optical component, 5 a . . . concave mirror, 6 . . .projection-receiving member (windshield) , 7 . . . housing, 8 . . .driver's line of sight, 11 . . . image projection device, 2, 21, 22 . .. optical element (lens) , 30 . . . control device, 31 . . . storagedevice, 32 . . . microcomputer, 33 . . . RAM, 34 . . . ROM, 41 . . .antiglare plate (glare trap) , 61 . . . navigation system, 62 . . .driving support electronic control unit (driving support ECU) , 63 . . .surroundings monitoring device, 60 . . . driver's viewpoint monitoringcamera, 63 . . . surroundings monitoring device, 101 . . . vehicle body.

1. An information display apparatus configured to display image information in a vehicle, the information display apparatus comprising: a display; and a light source configured to supply light to the display, wherein an image of the display is displayed as a virtual image, and wherein, in a vertical direction of the vehicle, a display position of the virtual image continuously changes from a distant position to a close position along a direction from a top to a bottom of the virtual image.
 2. The information display apparatus according to claim 1, wherein the virtual image is displayed by reflecting light emitted from the display by a windshield or a combiner of the vehicle.
 3. The information display apparatus according to claim 1, wherein the display position of the virtual image is set to a stopping distance which is a total of a free running distance and a braking distance of the vehicle or to a distance equal to or larger than the stopping distance.
 4. The information display apparatus according to claim 1, wherein one of the image information is alert information, and the alert information is for giving a warning of a presence of a pedestrian in front of the vehicle and/or a preceding vehicle.
 5. The information display apparatus according to claim 1 further comprising a concave mirror configured to reflect light emitted from the display toward a windshield of the vehicle, wherein the concave mirror has a rotating mechanism.
 6. The information display apparatus according to claim 1 further comprising: at least one lens configured to form an image of light from the display; and a mirror configured to converge or diverge the light the image of which has been formed in the at least one lens.
 7. The information display apparatus according to claim 1, wherein a display region of the virtual image moves in an up-and-down direction of the vehicle in accordance with a change in a depression angle with respect to the display region of the virtual image.
 8. The information display apparatus according to claim 1 further comprising circuitry configured to acquire information of the vehicle.
 9. The information display apparatus according to claim 8, wherein the information of the vehicle includes information of an intensity of external light around the vehicle, and the display position of the virtual image changes in accordance with the intensity of the external light around the vehicle.
 10. The information display apparatus according to claim 8, wherein the information of the vehicle includes a traveling speed of the vehicle, and wherein a viewing angle in a horizontal direction of a display region of the virtual image and a depression angle with respect to the display region of the virtual image are changed based on the traveling speed of the vehicle.
 11. An automobile comprising: an information display apparatus configured to display image information in the automobile, the information display apparatus comprising: a display; and a light source configured to supply light to the display, wherein an image of the display is displayed as a virtual image, and wherein, in a vertical direction of the automobile, a display position of the virtual image continuously changes from a distant position to a close position along a direction from a top to a bottom of the virtual image.
 12. The automobile according to claim 11, wherein the virtual image is displayed by reflecting light emitted from the display by a windshield or a combiner of the automobile.
 13. The automobile according to claim 11, wherein the display position of the virtual image is set to a stopping distance which is a total of a free running distance and a braking distance of the automobile or to a distance equal to or larger than the stopping distance.
 14. The automobile according to claim 11, wherein one of the image information is alert information, and the alert information is for giving a warning of a presence of a pedestrian in front of the automobile and/or a preceding vehicle.
 15. The automobile according to claim 11, further comprising a concave mirror configured to reflect light emitted from the display toward a windshield of the automobile, wherein the concave mirror has a rotating mechanism.
 16. A method performed by an information display apparatus configured to display image information as a virtual image in a vehicle, the method comprising: generating light by a light source; reflecting and projecting the light from the light source to a display; displaying an image of the display as a virtual image; and continuously changing, in a vertical direction of the vehicle, a display position of the virtual image from a distant position to a close position along a direction from a top to a bottom of the virtual image.
 17. The method according to claim 16, further comprising displaying the virtual image by reflecting light emitted from the display by a windshield or a combiner of the vehicle.
 18. The method according to claim 16, further comprising setting the display position of the virtual image to a stopping distance which is a total of a free running distance and a braking distance of the vehicle or to a distance equal to or larger than the stopping distance.
 19. The method according to claim 16, wherein one of the image information is alert information, and the alert information is for giving a warning of a presence of a pedestrian in front of the vehicle and/or a preceding vehicle.
 20. The method according to claim 16, further comprising reflecting light emitted from the display toward a windshield of the automobile with a concave mirror having a rotating mechanism. 